Method of Salaah

Q: What is the Sunnah method of going down in sajdah? Should we go down into sajdah without placing the hands on the knees, or go down with placing the hands on the knees?

Q: I would like to know when performing the 3 rakaats of fard maghrib, do you recite a surah in the third rakaat after reciting surah fatiha or do you just recite surah fatiha and then go into ruku?

Q: I am currently becoming hafiz at the age of almost 40 (please make dua that I reach completion). I practice what I have learnt during the day by reciting it in namaz and in nawafils. After Esha I come home from the masjid and I recite quietly in the sunnats of Esha and loudly in witr namaz and in nawafils thereafter. I do not pray loud in nawafils during the day because I have been told that you can't recite aloud in the sunnats of (say for eg. Esha, maghrib) and that you can't pray loud in nawafil during the day (only at night), is this true?

I find it so much easier and more helpful if I read aloud, I find that reading aloud helps me retain what I have memorised much better. For the sake of my purpose (hifz-e-quran) would it be ok for me to recite aloud in sunnats of maghrib/Esha, etc and in Ishraaq and chast namaz in the privacy of my own home (without disturbing anyone)?

Q: Is one's namaz valid if we don't read durood sharif and the dua in the last rakaat?

Q: One who reads only the word ha meem or yaseen in salaah, will it suffice for the fardh of qiraat?

Q: If we perform a fardh salaah which have sunnah muakkadah after it (zuhr, magrib, isha), when should we read dua after salaah? After the fardh salaah or after the sunnah muakkadah salaah, or after both?

Q: How long is it waajib for jalsah in salaah?

Q: In s​alaah after ruku while standing when one is reading rabana walakal hamd. Is salaah valid if most of rabana walakal hamd was read standing and maybe a little while moving down? If not and one just bent his knees a bit and moved his hands forward, then is it valid? 

Q: If one has to recite only one Ayah in a rakat of a Salah how long it should be?

Q: It is mentioned that a person's dua will be answered if he makes duaa after the fardh salaah. Does this mean that he should make dua after the fardh of the salaah or after the entire salaah is completed?